Stabilization of three-link acrobot via hierarchical linearization

Novel approach to linearize a multi-input nonlinear system is introduced and applied to control a three-link acrobot. The proposed linearizing method, referred as hierarchical linearization, consists of two ideas; directional decoupling and autonomization. Using these ideas, subsystems and the control inputs for these subsystems are constructed hierarchically. In this paper, the hierarchical linearization is applied to a three-link acrobot and linearizes the system partially. Owing to the proposed method, stable zero dynamics is designed. In numerical simulation, the validity of the controller designed by the proposed method is verified.